This invention concerns the removal of cutting fluid adhering to chips produced during the large scale machining of metal parts such as occurs in the production of engine components. Such machining uses cutting fluids which contain both oil and water which function to both cool and lubricate the cutting tool as the machining of a part proceeds. In such large scale production, the cutting fluid is collected from a number of stations and directed to filtration apparatus for removing the metal chips and other solids contaminants to allow recirculation of the cleaned cutting fluid back to the machining stations for reuse.
The metal chips are coated with the cutting fluid containing oil which tends to adhere thereto to not quickly drain away, such that the chips present a disposal problem. The metal chips can be salvaged if the quantity of fluid is reduced to a low level, i.e., 5% or less. Transport of the chip is also a problem since excessive drippage will occur unless the normally adhering fluid is removed.
So called xe2x80x9cchip wringersxe2x80x9d have been developed to remove residual cutting fluid from steel, cast iron, or aluminum chips by a centrifuging apparatus. See U.S. Pat. No. 6,129,851 for an example of such apparatus. Chip wringers operate at high speed and are costly to make and expensive to maintain.
Washing processes have also been proposed to remove the oil containing fluid, see for example U.S. Pat. Nos. 5,147,554 and 4,565,583, but those processes, typically using magnetic fields or hot pressurized water, are in practice likewise complex and costly.
It is the object of the present invention to provide a simplified process and system for removing water-oil based cutting fluids from machining chips which is less costly to purchase and operate than the prior systems.
The above recited object and others which will be appreciated upon a reading of the following specification and claims are achieved by a process in which the chips collected in one or more filters are deposited in a sluice and advanced by washing solution flushing jets emanating from nozzles directed down the sluice. The chips are thereby agitated and tumbled while being advanced along the sluice to be thoroughly washed.
The chips and washing solution move down the sluice and into a strainer tank where the washed chips are separated from the washing solution and thereafter drained and dried prior to being collected for disposal.
The washing solution preferably comprises a citrus oil based cleanser which is a powerful detergent of a low molecular weight which is commercially available in a composition which does not foam appreciably. The solution is preferably heated to speed drying of the chips after leaving the solution. A by pass flow of the washing solution is continually circulated through an ultra filter to remove oil washed from the chips, to allow continuous processing using recirculated washing solution.